Method for recovering data in a tape drive system
A method is disclosed. The method includes performing a first read operation at a tape drive, determining if a minimum number of data bytes have been recovered in the first read operation to perform error correcting codes (ECC), performing a second read operation if the minimum number of data bytes to perform ECC have not been recovered, determining if a minimum number of data bytes have been recovered in the second read operation to perform ECC, combining the recovered data bytes from the first read operation and the second read operation to form combined recovered data bytes, determining if a minimum number of data bytes are included in the combined recovered data bytes to perform ECC and performing ECC if the minimum number of data bytes are included in the combined recovered data bytes.
1. A method comprising:
performing a first read operation on a portion of a tape drive;
determining if a minimum number of data bytes have been recovered in the first read operation to perform error correcting codes (ECC);
performing a second read operation on the portion of the tape drive if the minimum number of data bytes to perform ECC have not been recovered;
determining if a minimum number of data bytes have been recovered in the second read operation to perform ECC;
combining the recovered data bytes from the first read operation and the second read operation to form combined recovered data bytes;
determining if a minimum number of data bytes are included in the combined recovered data bytes to perform ECC; and
performing ECC if the minimum number of data bytes are included in the combined recovered data bytes.
2. The method of claim 1 further comprising storing the recovered data bytes from the first read operation prior to performing the second read operation on the portion of the tape drive.
3. The method of claim 1 wherein combining the recovered data bytes from the first read operation and the second read operation comprises performing an Or-operation between the recovered data bytes from the first read operation and the second read operation.
4. The method of claim 1 further comprising performing a third read operation on the portion of the tape drive if the minimum number of data bytes included in the combined recovered data bytes are not sufficient to perform ECC.
5. The method of claim 4 further comprising:
determining if a minimum number of data bytes have been recovered in the third read operation to perform ECC;
combining the recovered data bytes from the third read operation and the combined recovered data bytes to form second combined recovered data bytes; and
determining if a minimum number of data bytes are included in the second combined recovered data bytes to perform ECC.
6. The method of claim 1 further comprising transmitting the full set of data bytes from the tape drive after performing ECC.
7. The method of claim 1 further comprising performing ECC if the minimum number of data bytes have been recovered in the first read operation.
8. An apparatus, comprising:
a tape medium;
a read/write head comprising read elements to read data from a portion of the tape medium; and a read/write controller having a data protect component to combine data bytes recovered from two or more read operations from the portion of the tape medium in order to accumulate a minimum number of data bytes to perform error correcting codes (ECC).
9. The apparatus of claim 8 wherein the data protect component performs ECC once the minimum number of data bytes have been accumulated.
10. The apparatus of claim 8 wherein the read/write controller determines if the number of recovered data bytes includes the minimum number of data bytes to perform ECC.
11. The apparatus of claim 10 wherein the read/write controller further comprises a buffer to store the recovered data bytes if the recovered data bytes do not include the minimum number of data bytes to perform ECC.
12. The apparatus of claim 11 wherein the read/write controller further comprises:
a pre-amplifier; and
automatic gain control to adjust for variations in signal amplitude.
13. The apparatus of claim 12 further comprising a processing unit to format the data bytes once ECC is performed.
14. An article of manufacture, comprising a machine-accessible medium including data that, when accessed by a machine, cause the machine to perform operations comprising:
performing a first read operation on a portion of a tape drive;
determining if a minimum number of data bytes have been recovered in the first read operation to perform error correcting codes (ECC);
performing a second read operation on the portion of the tape drive if the minimum number of data bytes to perform ECC have not been recovered;
determining if a minimum number of data bytes have been recovered in the second read operation to perform ECC;
combining the recovered data bytes from the first read operation and the second read operation to form combined recovered data bytes;
determining if a minimum number of data bytes are included in the combined recovered data bytes to perform ECC; and
performing ECC if the minimum number of data bytes are included in the combined recovered data bytes.
15. The article of manufacture of claim 14 wherein when accessed by a machine, further causes the machine to perform operations comprising storing the recovered data bytes from the first read operation prior to performing the second read operation on the portion of the tape drive.
16. The article of manufacture of claim 14 wherein combining the recovered data bytes from the first read operation and the second read operation comprises performing an Or-operation between the recovered data bytes from the first read operation and the second read operation.
17. The article of manufacture of claim 14 wherein when accessed by a machine, further causes the machine to perform operations comprising performing a third read operation on the portion of the tape drive if the minimum number of data bytes included in the combined recovered data bytes are not sufficient to perform ECC.
18. The article of manufacture of claim 17 wherein when accessed by a machine, further causes the machine to perform operations comprising:
determining if a minimum number of data bytes have been recovered in the third read operation to perform ECC;
combining the recovered data bytes from the third read operation and the combined recovered data bytes to form second combined recovered data bytes; and
determining if a minimum number of data bytes are included in the second combined recovered data bytes to perform ECC.
19. The article of manufacture of claim 14 wherein when accessed by a machine, further causes the machine to perform operations comprising transmitting the full set of data bytes from the tape drive after performing ECC.
20. The article of manufacture of claim 14 wherein when accessed by a machine, further causes the machine to perform operations comprising performing ECC if the minimum number of data bytes have been recovered in the first read operation.